To jam and learn Andymori - ハッピーエンド chords, your primary focus should be mastering these chords sequence: Eb, E, B, Eb, Abm and B. A strategic approach would be to train at 57 BPM initially, and then accelerate to the song's tempo of 116. Given the song's key of B Major, adjust the capo to align with your vocal range and chord preference.